Automobile drying plant

ABSTRACT

IN ORDER TO INCREASE THE OUTPUT CAPACITY AND TO IMPROVE THE EFFICIENCY OF STATIONARY OR TRANSPORTABLE DRYING PLANTS FOR WASHED VEHICLES OF THE TYPE USING A TUNNEL OR GANTRY COMPRISING SLOT NOZZLES CONNECTED TO A HIGH-PRESSURE BLOWER OF HIGH EFFICIENCY AND DIRECTING THE COMPRESSED AIR WITH HIGH VELOCITY AGAINST THE VEHICLE SURFACES TO BE DRIED, THERE IS PROVIDED HEAT-EXCHANGING MEANS HEATED WITH CHEAP ENERGY, FOR INSTANCE FUEL OIL BY MEANS OF AN OIL BURNER, AND ARRANGED AT THE DISCHARGE SIDE AND, IF OCCASION ARISES ALSO AT THE SUCTION SIDE OF THE BLOWER. BY CONTROLLING THE INCREASE OF THE AIR TEMPERATURE AT THE PRESSURE SIDE OF THE BLOWER IT IS POSSIBLE TO MAINTAIN A SUBSTANTIALLY CONSTANT DYNAMIC PRESSURE AT THE SLOT NOZZLES AT TEMPERATURES VARYING BETWEEN 20*C. AND 150*C. THEREBY ALLOWING THE DRYING PLANT TO ADAPT TO THE MOMENTARILY PREVAILING OUTPUT REQUIREMENTS. AT THE SAME TIME THE NOISE LEVEL OF THE BLOWER IS REDUCED SUBSTANTIALLY BY PROVIDING THE HEAT EXCHANGING MEANS WHICH ACTS AS SOUNDDAMPING MEANS. IN ADDITION THE HEAT-EXCHANGING MEANS MAY ALSO INCLUDE NOISE-DAMPING MEANS OR SEPARATE MUFFLING MEANS MAY BE PROVIDED IN ADDITION TO THE HEAT EXCHANGING MEANS.

June 15, 1971 A. PETERS AUTOMOBILE DRYING PLANT 2 sheetsLs'neet 1 FiledAug. 6, 1968 MMM P579@ INVENTOR M im ` Aftomey June 15, 1971 A PETERS3,584,395

AUTOMOBILE DRYING PLANT Filed Aug. 6, 1968 2 Sheets-Sheet 2 i@ mA Fig.2

20 3'0 40 5'0 a 7b 8'0 0 100 11'0 1220 'o 14'0 750 c INVENTOR -UnitedStates Patent O1 ce 3,584,395 AUTOMOBILE DRYING PLANT Armin Peters, 2Rosenweg, 452 Melle, Germany Filed Aug. 6, 1968, Ser. No. 750,542 Claimspriority, application Germany, Oct. 11, 1967, P 16 30 427.1 Int. Cl.F26b 19/00 U.S. Cl. 34-229 3 Claims ABSTRACT OF THE DISCLOSURE In orderto increase the output capacity and to improve the eciency of stationaryor transportable drying plants for washed vehicles of the type using atunnel or gantry comprising slot nozzles connected to a high-pressureblower of high eiiiciency and directing the compressed air with highvelocity against the vehicle surfaces to be dried, there is providedheat-exchanging means heated with cheap energy, for instance fuel oil bymeans of an oil burner, and arranged at the discharge sidel and, ifoccasion arises also at the suction side of the blower. By controllingthe increase of the air temperature at the pressure side of the blowerit is possible to maintain a substantially constant dynamic pressure atthe slot nozzles at temperatures varying between C. and 150 C. therebyallowing the drying plant to adapt to the momentarily prevailing outputrequirements. At the same time the noise level of the blower is reducedsubstantially by providing the heat exchanging means which acts assounddamping means. In addition the heat-exchanging means may alsoinclude noise-damping means or separate mufing means may be provided inaddition to the heat exchanging means.

BACKGROUND OF THE INVENTION (l) Field of invention This inventionrelates to stationary or transportable drying plants used primarily inautomobile garages for drying washed cars, wherein air sucked in by ahigh-pressure blower is directed with high velocity by slot nozzlesagainst the side and top surfaces of the car.

(2) Description of the prior art In smaller washing garages so-calledgantry dryers are used by moving them over the washed vehicle, while inautomobile washing lines stationary portal dryers are commonly employedthrough which the washed vehicles are moved by means of a oor conveyor.The dynamic air pressure generated in these dryers at the slot nozzlesdue to the great exit velocity is designed to blow olf the sprayed wateradhering to the vehicle while moving the vehicles past the nozzles witha dened distance, wherein the formation of water drops by water tensionmay assist this dynamic blow off procedure.

In any case, the vehicle must be wiped-off manually by a person after ithas passed the dryer to finally remove traces of drops or small dropletsthat might still adhere to the vehicles. A characteristic of this typeof air-jet drying with cold air is in the fact that the number ofpersons doing the wiping must increase when the number of vehiclespassing the plant increases, and attains a maximum in winter time at lowtemperature of the garage. In automobile washing lines of any capacitythe amount of work varies greatly and depends on the seasons and changeswith the weather.

In drying plants of the type the invention is concerned with it has beenrealized already that it is favorable to increase the temperature of thedischarge air directed against the surfaces of the vehicle relative tothe temperature of the air sucked into the blower, wherein certain3,584,395 Patented June 15, 1971 cooperating reactions on the surface ofvigorously moved water drops, or water strands, as well as absorptionreactions of the unsaturated masses of air are of great importance. Foreffectively increasing the discharge temperature initially the procedurewas as follows. An increase in temperature is effected by thecompression of the air in the high pressure blowers without addition ofheat, or emission of heat. This adiabatic increase in temperature is afunction of the total pressure diiference relative to the environmentair and amounts, for example, at an air pressure of 760 torr and a totalpressure difference of 800 kp./m.2 the temperature increases exactly6.6. Additionally a further temperature increase is effected which is afunction of the efliciency of the blower. The higher the operatingpressure and the poorer the operating efficiency of the blower thehigher is the actually achieved increase in temperature between theintake temperature and the discharge temperature. Measurements inexisting drying plants showed increases in temperature between 18 and 25C. with a blower efficiency between 25% and 30%. rllhus, during warmsummer days when the temperature in the washing garage was about 20 C.the discharge temperature at the nozzles amounted to about 40 C., andsatisfactory blow off and drying effects were achieved at an averagespeed relative of dryer and vehicle. However, the number of driedvehicles remains limited at a constant drying effect unless it ispossible to increase the dynamic pressure, or the discharge temperatureat the nozzles, or both, when the number of vehicles to be dried isincreased.

If, in a colder season, the intake temperatures drop then the actualincrease in temperatures achieved in the aforementioned manner do notsuice for an unobjectionable drying procedure, necessitating that forthe polishing by hand an increased number of persons must be employed,or the rate of travel of the vehicles must be decreased. In order toavoid the increased employment of persons it has been proposed toinstall two or even three drying units in series. But even then it wasnot possible to achieve the same drying effect as in warm seasons whenthe travelling rate of the vehicles was higher. Also, the installationof a plurality of dryers in series, particularly in washing lines, notonly causes an increase in costs of energy but equally in costs ofinvestment and space. In addition to this a noise level of approximatelydecibels is generated using only one drying unit and when a plurality ofdrying units is installed in series, the resulting noise level oftenattains the threshold of pain in the human ear. Attempts to install thehigh-pressure blower outside of the garage was not entirely successfulbecause even in this case the generated noise level near the drying zoneis too high and is insuferable for the worker and for the customerhaving his vehicle washed.

Due to the extremely poor eiciency of the hitherto used high-pressureblowers, the consumption of electric energy by the drive motors of theblowers is very high, so that the cost of energy of these dryers isextremely high. These energy costs are summing up whenever a pluralityof drying units are installed in series, so that often the addition of atransformer station becomes necessary.

Attempts to use the warm air of garage heating units for the drying ofvehicles has only brought a limited success since the increase intemperature with simultaneous decrease of the pressure at the nozzlesdid not suffice, and outside temperatures, directions of wind, and otherweather influences vary greatly and cannot be controlled.

Further, it has been attempted in connection with gantry dryers tosupply a large volume of air by separate high pressure blowers to eachslot nozzle directed against the vehicle surfaces with high jetvelocity. In this the intake air was heated at the intake side of theblowers by 3 heated combustion gases, or by means of heat exchangers,whereby actual increases in temperature up to 40 C. were attained.

But if the intake air at the suction side of the high pressure blower isderived from the heated garage, or the intake air is heated directly orindirectly, the dynamic pressure at the slot nozzles decreasesproportionally with the increase in temperature of the intake air, andthus the favorable effect of the increased temperature for the dryingprocess is lost again, or at least lost to a great extent, which meansthat when the air is heated at the intake side of the blower there is nopossibility to control the drying plant and adjust it to the frequentlyhourly changing vehicle-processing capabilities.

Therefore, in view of the known drying plants the object of thisinvention is to reduce the operating and investment costs considerably,to make the system independent of weather conditions and temperatureconditions in the washing garages, and to employ a minimum number oflaborers.

SUMMARY OF THE INVENTION For solving this problem the invention ischaracterized substantially in that in the iirst mentioned drying planta high-capacity blower driven by an electromotor is combined withheat-exchanging means heated with inexpensive fuel, for example fueloil, and arranged at the discharge side, or the discharge and suctionside of the blower.

The invention avoids the costly electric energy expenditure hithertocommon in using high-pressure blowers with high inner resistance, sincein using a high-capacity blower with an eiciency up to approximately 90%the consumed energy is nearly completely used for generating the desireddynamic pressure at the nozzles, while the heating of the air at thepressure and the suction side of the blower is achieved by a heatexchanger heated with inexpensive energy.

By means of heating the air at the pressure side of the blower thedynamic pressure increases at the slot nozzles proportionally to theincreasing heating temperature, whereby it is possible to control thedrying plant in dependence on hourly capacity of passing vehicles and inaddition the heat exchanger acts, or may especially be constructed as amuffler.

Particularly favorable working conditions are achieved if the air isheated at the pressure and suction side of the blower, because then itis possible to control the heating of the air upstream and downstream ofthe blower in such a manner that the dynamic pressure at the slotnozzles remains constant, or nearly constant, at increasing temperatureof the delivered air, whereby an adaptation to the hourly changingoutput capacity of vehicles is possible by controlling the dynamicpressure and/or the temperature.

The subdivision into the source of energy for the highcapacity blowerwith a high degree of eiciency, and the possibility of heating the airat lower temperature of the intake air at selected temperatures up toapproximately 150 C. leads to considerable savings in costs of energy,wages and investments and also in space requirements, whilesimultaneously damping the blower noise, primarily it is possible tocontrol the dryer in dependence on the desired, or the varying vehicleoutput.

The invention is further described below in connection with the drawingsshowing schematically as an example of one embodiment according to theinvention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 is a schematic layout of the drying plant, in which the air isheated at the pressure side of the blower with or without addition ofpreheated intake air;

FIG. 1A is a diagrammatic elevation of part of the drying plant;

4 FIG. 2 is a diagram of the dynamic pressure in dependence on thetemperature to which the air has been heated in different arrangementsof the heating means for the blower air.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the schematically illustratedembodiment according to FIG. l a drying plant for washing vehicles,particularly passenger vehicles is shown constructed in a gantry ortunnel fashion G adjustable to any output of vehicles. The vehicle orthe gantry may be displaced as shown B and C to eiect relative movementtherebetween.

This drying plant comprises only one high capacity blower 1, driven byan electromotor and a great volume of compressed air is delivered via adiffuser 2 and ducts to slot nozzles 4 directing the air at highvelocity towards the side surfaces and to slot nozzle 5 directing theair at high velocity toward the top surface of the vehicle. But,according to the invention, it is also possible to provide a pluralityof separate high capacity blowers for the nozzles. At the suction sideof the blower a muffler 6 shown in dotted lines is provided for dampingthe noise of the blower, and a heat exchanger 8 is mounted in thepressure side within which the compressed air is heated, particularly byan oil burner 9, or a natural gas burner, or the like, with inexpensiveenergy, which burner is adapted to the capacity of the blower and thedesired temperature increase of the compressed air at the nozzles, andwhich advantageously operates automatically.

This drying plant operates at an extremely low noise level since, on theone hand, a muler 6 is provided at the suction side and since, on theother hand, the heat exchanger 8 at the pressure side acts as a muffler,or may especially be constructed as a muler, or may be combined with amul-lier whereby the plant may be connected directly to the gantry ortunnel.

For a better understanding of the invention first the curves of thedynamic pressure at the slot nozzles in dependence on the temperature towhich the blower air is heated are considered in FIG. 2.

If the air is heated at the suction side of the blower in a known mannerthe dynamic pressure drops at the nozzles with increasing temperatures,as shown in solid lines. An improvement of the drying process of thevehicles with increased temperatures is correspondingly cancelledtotally, or at least to the greatest part, by the decreasing dynamicpressure, and consequently this heating of the air at the suction sideof the blower does not allow a control to adapt the plant t0 the hourlyvarying output of vehicles.

If, contrary to this, the air is heated by a heat exchanger at thepressure side of the blower, in accordance with the invention, thedynamic pressure at the slot nozzles rises proportionally to theincreasing temperatures, as illustrated in the curves shown in dottedlines, and thus it is possible to control the drying effect and adaptthe plant to the hourly vehicle output within certain limits and independence from the initial value of the dynamic pressure at roomtemperature.

Out of the dropping curves of the dynamic pressure when heating the airat the suction side of the blower and the rising curves when heating theair at the pressure side of the blower it will become evident that, ifboth types of heating are employed the conditions may be chosen in sucha manner that always a dropping and a rising curve may be superimposed,so that the resulting dynamic pressure remains constant, or nearlyconstant, over a temperature range between 20 C. and approximately C.,as, for example, illustrated by the line k in FIG. 2. Thus, it ispossible, by simply controlling the air temperature at both sides of theblower, to adapt the plant to an hourly changing vehicle output whichmay increase from a minimum to a maximum, and this, which is important,independently of dropping temperatures in the washing room since thetemperature of the air discharged out of the slot nozzles may beincreased up to a maximum of 150 C.

Corresponding to this extremely favorable solution one can proceedaccording to FIG. l in such a way that the heat exchanger 8 is installedin the pressure side of the blower, and that heated air, for examplecirculated air, is supplied to the suction side, wherein also a heatexchanger may be installed in the suction side. In case of the firstembodiment it is advantageous for dampening the noise to install themuier 6 in the suction side, but it is also possible to install asimilar muffler additionally in the pressure side if the heat exchanger8 for itself should not sufce to dampen the noise. These arrangementsare shown by the means 10 for controlling heating of the air upstreamand downstream of the blower 1. This means 10 can include a second heatexchanger, similar to the exchanger 8, or the like, for supplyingpreheated air to the blower at a rate such that the dynamic pressure atthe nozzles 4 and 5 remains substantially constant at temperatures ofthe discharged air between C. and 150 C. It can further include a muier,like muler 6, downstream of the blower.

What is claimed:

1. A drying plant for washed vehicles comprising in combination:

(a) a structure adapted to embrace the top and the sides of the washedvehicle;

(b) means effecting a relative movement between said structure and saidvehicle;

(c) at least one high-pressure air blower of high efciency driven by anelectric motor and having a suction side and a pressure side;

(d) lateral and upper slot nozzles on said structure and ductsconnecting said nozzles to the pressure side of said blower fordirecting the discharged air with high velocity at a substantiallyconstant dynamic pressure against the side and top surfaces of saidvehicle;

(e) at least one heat exchanger arranged between the pressure side ofsaid blower and said slot nozzles and fueled heating means at said heatexchanger for heating the air traversing same; and

(f) means for supplying preheated air to the suction side of said blowerat a rate such that the dynamic pressure at said nozzles remainssubstantially constant at increasing temperatures of the discharged airbetween 20 C. and 150 C.

2. A drying plant for washed vehicle comprising in combination:

(a) a structure adapted to embrace the top and the sides of the washedvehicle;

(b) means effecting a relative movement between said structure and saidvehicle;

(c) at least one high-pressure blower of high efciency driven by anelectric motor and having a suction side and a pressure side;

(d) lateral and upper slot nozzles and ducts connecting said nozzles tothe pressure side of said blower for directing the discharged air withhigh velocity at a substantially constant dynamic pressure against theside and top surfaces of said vehicle;

(e) at least one heat exchanger arranged between the outlet of saidblower and said slot nozzles and oil-fueled heating means in said heatexchanger for heating the air traversing same; and

(f) a second heat exchanger arranged at the suction side of said blowersupplying preheated air to the blower at a volume rate such that thedynamic pressure at said nozzles remains substantially constant atincreasing temperatures of the discharged air between 20 C. and 150 C.

3. A drying plant according to claim 2 further comprising sound-mufingmeans at the suction and pressure sides of said blower.

References Cited UNITED STATES PATENTS 3,254,426 6/1966 Lamb et al.34-156X 1,970,674 8/1934 Seibert et al. 34-229X 2,300,266 10/ 1942Smellie 15-326 2,440,157 4/1949 Rousseau 34-229 2,758,392 8/1956 Vani etal. 34-229 3,009,257 11/1961 Scott 34-160X 3,403,456 10/1968 Smith34-160 FREDERICK L. MATTESON, JR., Primary Examiner H. B. RAMEY,Assistant Examiner

